Treadstone Associates
Case File № 175 · Rental & Investment

The triplex that killed the ratios twice

add-back vs. offset in Fredericton

A three-unit Fredericton rental purchase pushed TDS to 44.5% under a bank's 50% add-back treatment — just over the line. Re-worked under an 80% offset lender, the same file qualified at 27.1%.

New BrunswickUninsured · 20% downFiled August 7, 20265 min read
44.5%

TDS under Bank A’s 50% add-back — just over guideline

27.1%

TDS under Lender B’s 80% offset — approved with real margin

3/3,900

units in the triplex, totalling $3,900/month in signed leases

Anonymized illustration. The borrowers, dollar figures, and rates in this file are an illustrative composite — no real client is identifiable, and any rate shown is illustrative, not a quote. The rules are real: every regulatory figure is cited to its source in the Sources section, and the math computes exactly as shown.

№ 01

The client

A couple already owning their own home decided to buy a three-unit rental property in the Fredericton market as a pure investment. All three units came with tenants and signed leases in place — a fully-occupied, cash-flowing investment property mortgage from day one. What nearly stalled the deal had nothing to do with the property and everything to do with which lender's rental-income policy the file landed on first.

Borrowers

Couple, both salaried

$155,004/year combined

Own housing

$2,600/month

Their existing principal-residence carrying cost

Other debt

$400/month

Vehicle loan

Purchase

$540,000 triplex, Fredericton

20% down ($108,000); uninsured investment property

Leases

$1,450 + $1,300 + $1,150 = $3,900/month

All three units tenanted, signed leases

The triplex's own carrying costs, before any rent is credited:

Subject property (qualifying)Monthly
P&I at the qualifying rate ($432,000 at 7.09%)$3,050
Property tax, whole triplex$420
Heat (lender-standard estimate)$150
Total qualifying carrying cost$3,620
№ 02

The problem

The couple's own bank applies an add-back for rental income on a non-subject property: add half of the gross rent to income, and carry the full carrying cost as a liability. That treatment is common, and on a three-unit property it moves less than it might on a single unit — the file still missed.

The add-back arithmetic

  • Income used: $12,917 + $1,950 (50% of the $3,900 total rent) = $14,867/mo
  • Liabilities: $2,600 own housing + $400 vehicle loan + $3,620 full triplex carrying cost = $6,620/mo
  • TDS: $6,620 ÷ $14,867 = 44.5% — a hair over the bank's guideline

Half a point over guideline is still a decline. The rent from three fully-tenanted units genuinely does most of the work of carrying this property — but the add-back's income boost was not enough to offset carrying the full $3,620 as a straight liability.

№ 03

The numbers

As an uninsured investment purchase at 20% down, there is no default-insurance premium to structure — the qualifying-rate test on the mortgage itself is the whole of the arithmetic before rental treatment even enters the picture.

Structuring the uninsured purchaseAmount
Purchase price$540,000
Down payment (20%)−$108,000
Mortgage$432,000
Rate & paymentsFigure
Contract rate (illustrative, not a quote)5.09%
Minimum qualifying rate — greater of contract + 2% and 5.25%7.09%
Monthly P&I at the qualifying rate — the ratios run on this$3,050
Monthly P&I at the contract rate — what would actually be paid$2,535

Add-back vs. offset, on the same three leases

The 50% add-back and 80% rental offset percentages are illustrative of two common structures; each lender publishes its own, as covered in rental income offset methods, compared.

TDS lineBank A — 50% add-backLender B — 80% offset
Rent treatment+$1,950 to income$3,900 × 80% = $3,120 credited against costs
Subject property net liability$3,620 (full)$3,620 − $3,120 = $500
Income used$14,867$12,917
TDS vs. guideline44.5%  ✗27.1%  ✓

The offset applies the rent against the property's own costs before anything reaches the ratios; only the $500 shortfall lands as a liability. The same three leases swing the file more than 17 TDS points.

№ 04

The solution

A New Brunswick mortgage broker treated the bank's decline as a statement about that lender's rental-income policy on multi-unit properties, not a verdict on a fully-tenanted triplex. Every unit had a signed lease and a paying tenant — the only variable that mattered was which lender's guidelines got to read those leases.

The file moved to a lender whose published policy offsets gross rent against the subject property's own carrying costs, crediting the shortfall rather than the full cost as a liability. That single change turned a marginal decline into an approval with real margin.

All three signed leases
Two years of NOAs for both borrowers
90-day down-payment history
Property tax bill and insurance quote for the triplex
Purchase agreement and MLS listing

With TDS at 27.1% instead of 44.5%, underwriting had no reason to push back on any single line item — the file simply worked. The couple's own home financing was untouched throughout; nothing about their existing mortgage or its terms needed to change to make the triplex purchase qualify.

№ 05

The outcome & the closing math

Approved and funded as an uninsured triplex purchase at 20% down. The closing cash beyond the down payment:

Cash due at closing (beyond the down payment)Amount
New Brunswick's flat 1% real property transfer tax on $540,000$5,400
Legal fees & adjustmentsvaries

New Brunswick charges a flat 1% on the greater of the sale price or the assessed value, with no first-time-buyer exemption — the same rate applies regardless of unit count.

№ 06

What to take from this file

  • 01A multi-unit property does not automatically make an add-back safe. Half of $3,900 in rent still was not enough to offset carrying the full property cost as a liability — know the actual math before you promise a client an outcome.
  • 02The swing between add-back and offset scales with the number of units. This file moved more than 17 TDS points on three leases; a single-unit file typically moves less.
  • 03A decline that misses by half a point is still a decline — and still a data point about the lender, not the property. Three fully-tenanted units and clean credit did not change the outcome at the first lender.
  • 04Budget New Brunswick's flat 1% transfer tax regardless of the property's unit count. There is no first-time-buyer relief on this tax, and it applies the same way to a triplex as to a single-family home.

Sources

Every regulatory figure in this file traces to one of these primary sources. Client details and anything that varies by lender are illustrative, as flagged below.

Illustrative in this file — lender-specific, not rules:

  • 5.09% contract rate — rates move daily; not a quote.
  • 50% add-back / 80% offset percentages — each lender publishes its own rental-income treatment.

Authority & provenance

How this case file was built

We publish the origin, the verification method and the reviewer for every case file, so you can judge how far to trust it before you rely on it with a client.

Where it comes from

Derived from files handled by Treadstone’s fulfillment desk and from scenarios contributed by partner brokerages. Names, employers, exact amounts and dates are changed so no client or file is identifiable.

Provenance: Composite — a pattern seen repeatedly on fulfilled files, not a single transaction.

What is verified

Every regulatory figure traces to a primary source listed above and was checked against it on the date shown. The arithmetic is recomputed by machine on every rebuild.

Anything that varies by lender is labelled illustrative rather than stated as a rule.

Who reviewed it

Reviewed for Canadian regulatory accuracy before publication, and re-checked whenever a cited rule changes.

Reviewed by: Nicholas Parson, Treadstone Associates — reviews every case file before publication.

First published 7 August 2026Rules last verified 7 August 2026Next scheduled review 7 February 2027

This case file is professional reference material for licensed mortgage professionals. It is not advice to a borrower, and it is not a lender commitment. Insurer rules, qualifying rates and provincial taxes change — confirm the current position with the insurer, regulator or lender before you rely on any figure here in a live file.

Treadstone fulfillment

Files like this are daily work for our desk.

Document collection, ratio math under multiple treatments, lender placement notes, and submission-ready packaging — for Canadian mortgage brokers who would rather be in front of clients.